Patent Document 1 discloses a biaxially stretched, blow molded bottle made of a polyethylene terephthalate (PET) resin (hereinafter sometimes referred to as the PET bottle), which is used for such products as teas, juices, and the like, that require hot filling or heat treatment processes, such as sterilization.
Thus, in the case of those PET bottle used for hot filling with teas, juices, etc., or for the heat treatment of some products, at a temperature in the range of about 80 to 90° C., use is made of a so-called heat-resisting neck which has been treated to give improved resistance to heat deformation. As the known thermal crystallization treatment processes, there are a process utilizing a hot-blast nozzle, such as described in Patent Document 2, and a process utilizing an infrared heater.